It’s Best Not to Move Mature Peonies
Even if you plant them at precisely the right depth, with dormant buds less than 2 inches (5 cm) deep, often the plant will not flower again for several years, sometimes for up to a decade. To be honest, sometimes you will manage to move a mature peony with success, but generally transplanting mature plants gives disappointing results. It just seems that adult peonies have difficulty accepting any change in their situation. So rather than transplant the mother plant then wait for several years for it to recover, divide the plant instead. Dividing peonies rejuvenates them… and the young peonies that result from such division settle in much more readily than would a mature plant.